Microelectromechanical systems have gained great economic importance in the meantime. The majority is formed here by microelectromechanical sensors which are used, in particular, in the consumer sector and in the automotive sector as acceleration and pressure sensors.
Such pressure sensors are based on substantially the same functional principle: a pressure difference results in deformation of a diaphragm in the pressure sensor. This deformation of the diaphragm, which is proportional to the pressure difference, is measured. In this respect, two corresponding methods for the evaluation are already known:
In the capacitive method, the diaphragm is configured in such a manner that a capacitance changes as a result of the diaphragm deformation. The corresponding capacitance change is recorded and this capacitance change is then used to calculate the pressure difference or the corresponding pressure.
The second evaluation method is based on the so-called piezoresistive effect. Piezoresistors are arranged on or in the corresponding diaphragm. A voltage is then applied to the piezoresistors. If the diaphragm is deformed, the electrical resistance of the piezoresistors is also changed thereby, that is to say the diaphragm deformation is measured as the resistance change. A pressure sensor based on the piezoresistive effect is disclosed, for example, in DE 10 2008 033 592 A1.